Internal combustion engine silencers



R. MOREAU INTERNAL COMBUSTVION ENGINE SILENCERS June 4, 1963 2Sheets-Sheet 1 Filed Dec. 21, 1959 mu W A N MM W Vod. W MMW A 5 ma .wo F

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INTERNAL COMBUSTION ENGINE SILENCERS 2 Sheets-Sheet 2 Filed Dec. 21,1959 /A/vEA/To REA/E MoREA U United States Patent 3,092.,206 INTERNALCOMBUSTION ENGINE SILENCERS Rene Moreau, 81` Ave. Armand Huysmans,Brussels, Belgium Filed Dec. 2.1, 1959, Ser. No. 860,938 Claimspriority, application Belgium Dec. 29, 1958 6 Claims. (Cl. 181-68) -Thepresent invention rel-ates to silencers for internal combustion engines.

It is an object of this -invention to provide a silencer which -issuperior to 'that of known silencers.

The present invention provides a silencer of novel internal construction'and highly efficient action.

The silencer according to the invention comprises a casing, a plur-alityof double-walled baffies and means for fixing the bafiles in positionwithin -the oasing, the oasing being 'thus divided into a p'lurality ofintercommunicating compartments by means of the batfies, 'the bafilesbeing staggered so that exhaust gases from the engine must follow asinuous course, and each of the bafi'les being constituted from a planeperforate wall and a plane imperforate wall, such walls being separatedby a short distance, whereby a chamber is formed between them into whichthe exhaust gases may expand.

The perforations in the baffle `are conveniently of circular shape andabout 2 to 3 mm. in diameter. Owing 'to 'the perforated wall of thesegmentary member on which the exhaust gases impinge, a characteristicsreduction in noise is obtained 'as a consequence of a known physicaleffect and a silencer is thus given which is much more effective thanknown silencers.

In one embodiment of the -invention, the 'bafiies are fixed in positionperpendicular to the longitudinal axis of the casing. In thisembodiment, the fixing means can conveniently comprise spacing ringsbetween the baffles, 'and longitudinal rods passing through holes in thebaffles.

In another, preferred, embodiment, the baflles are fiJ-(d in position atan oblique angle to the longitudinal 'axis of the casing. The fixingmeans can in this embodiment con'sist of a lining member inserted withinthe casing and being provided with pai-rs of grooves which engage withthe bafiles. The casing and lining can thus be two pipes ofsufficient-ly differing 'diameters as to allow one pipe, which bearspairs of grooves on its linner surface, 'to slide within -the otherpipe. The :two pipes may be held together by two cap members, one ateach end of the silencer, which members, also car-ry the inlet andoutlet pipes for -the exhaust gases.

This second embodiment is a very effective silencer, and substantiallyreduces any excess internal pressure. The preferred fixing method iseasy lto assemble and 'the lining member increases the rigidity of thesilencer.

Other characteristics of the invention, which are only given by way ofexample, will appear from the follow- .ing description taken inconjunction with the accompanying drawings. In the drawings:

FIG. 1 shows 'a longitudinal section of a first embodiment of 'theinvention;

FIG. 2 is a -transverse sectional view of the silencer taken alongsection line 2-2 of FIG. l, as seen from the left hand end of FIG. 1;

FIG. 3 is a transverse section of the casing;

FIG. 4 is a perspective view of one of 'the doublewalled 'balfie's;

FIGS. 5 'and 6 show, respectively, the plane and perfora-te walls of abafile, and FIG. 7 -is a Vertical sectiona'l view of the perforate walltaken along the line 7-7 of FIG. 6;

3,092,20 Patented .l'uineV 4, 1 963 "ice FIG. 8 shows a spacing ring inVertical cross-section, `as it would appear along the line 8-8 of FIG.2;

FIGS. 9 and 10 show, in longitudinal cross-section, the pipesconnecting, respectively, the silencer with the engine and with theatmosphere;

FIG. 11 lis an end elevational view of the pipe shown in FIG. 10;

FIG. 12 is a longitudinal sectional view of a second embodiment of lthesilencer, also showing the cap members;

FIG. 13 is a longitudinal cross-section of the inner pipe alone of FIG.12; and

FIG. 14 is ya transverse section through the two inner pipes of FIG.y 12as -assembled The silencer shown in FIGS. l-ll consists of la casing 4(FIGS. 1-3) within which are arranged at intervals double-walledbafiles, which are spaced apart by means of spacing rings 5 (FIGS. 1, 2vand 8) and are held in position by 'two longitudinal rods 9, one ofwhich is seen in FIG. 1, which pass through holes in -the bafiles. As isseen from FIG. l, the baffles are staggered so 'as to cause the exhaustgases 'from |the engine to 'take the path shown by the arrows 10.

It will be seen from FIGS. 4-8 that each of 'the doublewalled bafflesconsists of a plane wall 7 and a wall 3 perforated by 'a number of'small holes 6, the two walls being joined by a part-annular segment 8.Holes are provided in the walls for vthe passage of the rods 9.

The exhaust gases from the engine enter the pipe 12, which is connectedto the engine by the cap member 13 and to the silencer 4 by Ithe capmember 14, travel in the d'irection of 'the arrow 11 in FIG. 9, 'andenter the silencer, where they -impinge successively against theperfora-ted walls 3, =thus lessening the noise. The g-ases fina-llyescape in the direction of the arrow 11 in FIG. 10 to the atmospherethrough the exhaust pipe 16 mounted on the 'silencer by means of the capmember 15.

According =to the preferred embodiment shown in FIGS. 12 to 14, theinner pipe 18 is provided with pairs of grooves 20 located in staggeredrelationship into which |the associated perforated walls 3 'andimperforate walls 7 are mounted and fiXed obliquely.

The inner pipe 18 is concentrically surrounded by the outer casing pipe4 .and it will be seen from FIG. 12 that the walls yof :the baflles aremounted in the pa'i'rs of `grooves 20 and 'that each pair contains aperforated wall 6 and an imperforate wall 7. Each pair of adjacent wallelements 6 and 7 cooperate to form a double-walled batfie. Thesedouble-walled bafilles are staggered 'so that the exhaust gases arecaused to take the path shown by 'the arrows 10 in FIG. 12.

The two concentric pipes are maintained in position by cap members 24and 25 which are provided respec- 'tively with an exhaust gas inlet pipe21 and an exhaust gas Outlet pipe 22.

This inclined 'arrangement of the lbaffles in the preferre'd embodimentconsiderably faoilitates dis'charge of the ex'haust gases and reducesany excess pressure inside the device. The provision of the inner pipe18 and vthe cap members 24 and 25 considerably facilitate zassembly ofthe device and increase its rigidity.

It should be mentioned that, without exceeding the scope of -the presentinven-tion, :the oblique disposition of the baffles in the p-referredembodiment can be provided by any other device, located inside thesilencer, which is equivalent to the inner pipe provided with grooves.Any suitable thermal and acoustic insulating material can be insertedbetween the inner pipe and the outer pipe by 'adapting their di-ametersaccordingly.

I claim:

1. A silencer for internal combustion engines, comprisi 3 ing a casing,a plurality of double-walled baffles, 'and means for fixing the bafiesin position within the casing, the casing being 'thus divided into aplurali'ty of interoommunicating .comp'artments by means of 'thebafiles, the bafes being staggered so that exhaust gases from the enginemust follow a sinuous course, 'and each of the baffies being constitutedfrom a plane perforate wall and a plane imperforate wall, such wallsbeing separated by a short distance whereby a chamber is formed betweenthem into which lthe exhaust gases may expand.

2. A silencer for internal combustion engines, comp'rising a casting,arplurality of double-walled baflles, 'and means for fixing the bafflesin position perpendicular to the -longitudinal axis of the casing, thecasing being thus divided into a plurality of intercommunicatingcompar'tments by means of lthe b'affles, the baffles being staggered sothat exhaust gases from the engine must follow va sinuous course, andeach of the baflles being eonstituted from a plane perforate wall and aplane imperforate wall, such walls being separated by a short distancewhereby a Chamber is formed between them into which the exhaust gasesmay expand.

3. A -silencer for internal combustion engines, comprising a casing, aplurality of double-walled baflles, and means for fixing lthe baffles inposition at an oblique angle to the longitudinal a'Xis of the `casing,the `oasing being thus divided into a plurality of intercommunieatingcom- 'partments by means of the bafiles, the bafiies being Staggered sothat exhaust gases from the engine must follow a 'sinuous course, andeach of the bafies being oonstituted from a plane perforate wall and aplane imperforate wall,

such walls being separated by a short distance whereby a Chamber isformed between them into which the exhaust gases may exp'and.

4. The silencer of claim 2, wherein the means for fixing the bafiles inposition within the oasing includes spacing rings located betweensuc'cessive pairs of btafiies and longitudinal rods passing ythroughholes in the bafiies.

5. The silencer of claim 3. wherein 'the means for fixing t'he bafflesin position within the casing consists of a lining member insertedwithin the casing, the lining member being provided with pairs ofgrooves engaging with the `periphera'l portions of the respectivebaffles.

6. A silencer according to claim 5, which also comprises la oap memberat ea'ch end for connection of the silencer to a gas inlet pipe and agas outlet pipe, the eap members serving to secure the lining member tothe c-asing.

References Cited in the file of this patent UNITED STATES PATENTSv1,030347 Swearingen June 25, 1912 1,0`66,341 Thomson July 1, 19131,983,304 Olsen Dec. 4, 1934 1,998,386 Powell Apr. 16, 1935 2,541,373McLeod Feb. 13, 1951 2,896,743 Bradshaw July 28, 1959 p FOREIGN PATENTS470,904 Italy Apr. 29, 1952 1,126,701 France July 30, 1956

1. A SILENCER FOR INTERNAL COMBUSTION ENGINES, COMPRISING A CASING, APLURALITY OF DOUBLE-WALLED BAFFLES, AND MEANS FOR FIXING THE BAFFLES INPOSITION WITHIN THE CASING, THE CASING BEING THUS DIVIDED INTO APLURALITY OF INTERCOMMUNICATING COMPARTMENTS BY MEANS OF THE BAFFLES,THE BAFFLES BEING STAGGERED SO THAT EXHAUST GASES FROM THE ENGINE MUSTFOLLOW SINUOUS COURSE, AND EACH OF THE BAFFLES BEING CONSTITUTED FROM APLANE PERFORATE WALL AND A PLANE IMPERFORATE WALL, SUCH WALLS BEINGSEPARATED BY A SHORT DISTANCE WHEREBY A CHAMBER IS FORMED BETWEEN THEMINTO WHICH THE EXHAUST GASES MAY EXPAND.